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Syphilis Bug: The Structure Of Treponema

March 11, 2010

Researchers hailing from the University of Connecticut Health Center, the Wadsworth Center, The Forsyth Institute, and the CDC have made use of the latest technology to clarify the exact molecular structure of the bacterium responsible for syphilis, Treponema pallidum. Before now, the architectural details of treponema were unknown. But because of this new research, the bacteria can now be seen in three dimensions (3-D). For the first time, scientists can see a true image of this pathogen and its heretofore unknown characteristics. The researchers hope that this discovery may help combat the spread of this sexually transmitted disease (STD).

3-D Image of Syphilis Bacteria

The research team used cryo-electron tomography (CET) to spot the difference between treponema pallidum and various other gram-negative bacteria. CET is a kind of microscope that can be used to generate a 3-D image by analyzing samples from two-dimensional images at very low temperatures.

The results of this research were featured in the last issue of the year for the Journal of Bacteriology. Lead author of the study, Jacques Izard, Ph.D., says this work gives researchers a crystal clear picture of a cell as it exists in real time. Izard comments that this work changes forever the way scientists will study Treponema pallidum. "Having an accurate architecture of the cell provides important insight for understanding how it becomes invasive in the human body. With this information we may learn how to stop disease progression."

Sharp Decline in Syphilis

During the 90's, there was a sharp decline in the rates of primary and secondary syphilis. However, the CDC has observed a spike in the rate of this STD since the year 2000. Since that time there have been 36,000 cases recorded every year. The increase has been observed in both sexes and also in newborns in the form of congenital syphilis.

After the genome sequence for Treponema pallidum was published more than a decade ago, scientists had a much better understanding of the makeup of this bacterium. However, scientists have not been able to learn much about how the various components of the bacterium combine to make such a fierce and evasive pathogen. CET has become an important tool for connecting the dots of medical knowledge. In this technique, slim films of individual cells are frozen so as to preserve the structure of the cells. In this way, they retain the characteristics of their most natural state. Traditional microscopy involves a certain amount of degradation of the cells because of the manner in which samples must be prepared for viewing. In CET, the cell sample is tilted with the help of an electron microscope. This generates a series of images that when combined, create a 3-D image.